Mobile telephone network-based system for detection and location of hazardous agents

ABSTRACT

A system for detecting hazardous agents is based on cellular telephone networks. The cellular telephones in public circulation have at least one detector for detecting at least one hazardous agent and broadcast alarm packets upon detecting the hazardous agent. A computer or computer network interconnected with telephones by the cellular telephone network processes the alarm packets and sets an alarm condition for the hazardous agent in a vicinity of the cellular telephone by calculations based upon alarm packets from other telephones with detectors for the hazardous agent in the vicinity. A map of the contaminated area is also created.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.10/961,474 filed Oct. 8, 2004, the contents of which are incorporated byreference herein in their entirety for all purposes.

BACKGROUND OF THE INVENTION

The present invention is related to electronic systems for the detectionand location of hazardous agents and, more particularly, to such systemsbased upon mobile telephone networks.

Sources of hazardous agents, such as biological, chemical, andradioactive materials, are plentiful in modern society and thepossibilities of their release must be faced. Furthermore, given thepresent threat of terrorism, the dangers of the purposeful release ofthese agents is also a real possibility. Hence there is the need for anetwork of ubiquitous detectors which are capable of sensing suchbiological, chemical, and radioactive agents.

Various networks, detectors and combinations of networks and detectorshave been proposed in response. One proposal has been the deployment ofsuch detectors in simple combination with, or as an integral part of,cellular (or cell) telephones. Cell telephones are ubiquitous in modernsocieties and are transported everywhere. As normally used telephones,the telephone owners are likely to keep the telephones charged and ingood working order. Canadian Patent No. 2,418,612, which issued toMarian Gavrila and Gabriel Patulea, describes the incorporation ofchemical, radiation, and biological agent detectors in cell phones andU.S. Pat. No. 6,697,645, which issued to J. M. MacFarlane, discloses theincorporation of environmental sensors into cellular phones.

Efforts at numerous national laboratories, universities, and businesseshave focused mostly on sensor development. For example, LawrenceLivermore National Laboratory is currently developing radiationdetectors which can be embedded in PDA (Personal Digital Assistant)/celltelephone devices which are part of a wireless network known as RadNet.These devices are to be deployed with specially trained personnel, suchas firefighters, utility workers, police, and custom agents, as a firstresponse team. But the relatively low number of such people compared tothe general population means that the detectors, or sensors, mustnecessarily be highly sensitive and accurate. These requirements implythat deployment of such a network system is likely to be many yearsaway. Other efforts include research on wireless networks of autonomoussensor devices; e.g., Graviton Corp. of San Diego is developing anetwork independent of existing cell telephone infrastructures.

Despite these efforts, these network systems suffer from variousdeficiencies, such as lack of geographical coverage, and high costs ofinstallation and maintenance. The distribution of detectors/celltelephones to special personnel limits the distribution of the sensornetwork. Sensitive and accurate detectors raise the initial andmaintenance costs of the sensor/PDA/cell telephone (or autonomoussensor) devices and the installation of special wireless networksfurther adds the total of network system costs.

On the other hand, the present invention provides for a network systemwhich is inexpensive to operate with easy installation and lowmaintenance costs.

BRIEF SUMMARY OF THE INVENTION

The present invention provides for a cellular telephone network-basedsystem for detecting hazardous agents. The cellular telephone network iscapable of physically locating cellular telephones in the network andthe system has cellular telephones in public circulation with eachcellular telephone having at least one detector for detecting at leastone hazardous agent and broadcasting over the cellular telephone networkat least one alarm packet upon detecting the hazardous agent. The systemalso has at least one computer interconnected with telephones by thecellular telephone network for processing the alarm packet and settingan alarm condition for the hazardous agent in a vicinity of the cellulartelephone by calculations based upon alarm packets from other telephoneswith detectors for the hazardous agent in the vicinity. The calculationsinclude determination of a level of contamination of the hazardous agentin the vicinity and integration over the level of contamination of thehazardous agent over the vicinity to determine whether a result ofintegration exceeds an alarm threshold. The calculations also includeadjusting for the number of telephones broadcasting alarm packets forthe hazardous agent in the vicinity with respect to the total number oftelephones capable of detecting the hazardous agent in the vicinity.

The present invention also provides for a method of operation in asystem based on a cellular telephone network having a plurality ofcellular telephones in public circulation, each cellular telephonecapable of detecting one or more hazardous agents and being located bythe cellular telephone network. The method has the steps of: receivingan alarm packet from any of the cellular telephones responsive todetection of a hazardous agent, the alarm packet including dataidentifying the hazardous agent and a cellular telephone base station incommunication with the telephone; determining a level of contaminationof the hazardous agent in the vicinity; integrating the level ofcontamination over the vicinity; and determining whether a resultingintegration value exceeds a threshold to determine whether an alarmcondition for the hazardous agent in the vicinity exists. The methodalso has the step of adjusting the level of contamination for the numberof telephones broadcasting alarm packets for the hazardous agent in thevicinity with respect to the total number of telephones capable ofdetecting the hazardous agent in the vicinity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a representation of a mobile telephone network-based systemaccording to one embodiment of the present invention;

FIG. 2 is a flow chart of operations of a cell telephone upon thedetection of a hazardous agent, according to one embodiment of thepresent invention;

FIG. 3 is a flow chart of computer operations upon receipt of alarmpackets from a cell telephone, according to one embodiment of thepresent invention.

FIGS. 4A and 4B are flow charts of computer operations in alarm mode,according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides for a cellular, or cell, telephonenetwork-based system using sensitive but less accurate detectors (orsensors) deployed broadly amongst the general cell telephone-carryingpublic. The network system can function as a first tier in amulti-tiered network for raising an alarm and eliciting an initialresponse against hazardous agents which have been released into thepublic environment. The system can produce a digital map of anagent-contaminated area and identify the most likely point of agentrelease. This allows a better directed secondary response to investigatea possible attack. The same map can be used to track and predict theprobable spread of the contaminants. Given the uncontrolled environmentin which cell telephones operate, the present invention creates thecontamination map without depending on perfectly functioning celltelephones and readily accommodates increasingly capable sensors asconsumers acquire newer telephones.

The system of the present invention operates with the following generalcomponents as illustrated by the representational drawing of FIG. 1:consumer cell telephones 10; services which can locate any cellulartelephone 10, such as provided by the cellular telephone base stations12 of a cellular network 11 operating under enhanced 911 (E911)requirements; local wind velocity data, such as collected or calculatedby weather services 16; and one or more computers 15 connected to thecellular telephone network and operating as described below.

The cell telephones 10 which are part of the system are ordinarycellular telephones circulating in public and using the existingcellular network infrastructure. But other wireless network devices,such as 802.16 terminals, wireless LAN and BlueTooth transceivers, arepossible where in common use and where the locations of the devices canbe determined through the network. Hence the term, cellular or celltelephones, is used to include devices which are in widespread publicuse, locatable, and interconnected by wireless communication networks.

Each telephone (or device) 10 is equipped with one or more detectorscapable of sensing one or more hazardous agents, including biological,chemical, or radioactive materials. In the sales of these telephones tothe public, the telephones 10 are distributed so that the telephones ina given cell area have the sensing capabilities of the full spectrum oflikely hazardous agents. Statistical means are used to ensure a highprobability that each cell area has the full agent detection coverage.

The telephones 10 operate automatically in accordance with the presentinvention. Upon detection of a dangerous agent by a detector, enhancedfirmware in the telephone 10 holding the detector broadcasts alarm datapackets over the cellular network 11 to indicate a danger or threat. Thelocation of any telephone 10 in communication with the cellulartelephone network 11 is capable of being determined by the base stations12 of the network 11 operating under E911 standards. E911, or enhanced911, is a set of requirements by the U.S. Federal CommunicationsCommission, which imposes the capability of locating a cellulartelephone within a certain resolution distance. The distance iscurrently 100 m, though this resolution distance may be upgraded overtime. The present invention uses the capability of the E911 locationservice to rapidly locate a large number of cell telephones in a typicalcell-sized region.

The present invention also uses wind velocity data at sufficientlydistributed and large number of locations so as to provide wind speedand direction information with sufficient resolution down to the size ofa typical telephone cell. Other meteorological data which might affectagent propagation, e.g., precipitation, may also be collected forfurther refinement of the contamination tracking process. Sites fromweather services 16 may provide the data. Alternatively or concurrentlywith weather service data, data from meteorological instruments locatedat the cell base stations 12 may be used where the potential for attackis high and/or the terrain is complicated. For open areas, weatherservice data which has resolution measured in hundreds of meters issufficient.

Finally, the present invention uses one or more computers 15 which areconnected to the cell telephones through the cellular network 11. Asrepresented in FIG. 1, the cellular network 11 includes cellular basestations 12 which are interconnected by mobile transport serving offices14 to each other and to the ordinary public switched telephone network(PSTN). Through the PSTN the telephones 10 are connected to the Internetwhich, together with the PSTN, is represented by a cloud 13 in FIG. 1.Only one computer 15 is shown in FIG. 1 but it is should be understoodas representing a plurality of computers 15 connected to the telephones10 through the Internet, the PSTN and the cellular network 11.Preferably the computers themselves are interconnected by a network. Thecomputers 15 initiate the E911 locator service, collect wind data, andcreate the digital contamination map, among other functions, asdescribed in greater detail below.

The detection of a hazardous agent by a detector in a telephone 10starts telephone operations after the initialization step 20, asillustrated by the flow chart of in FIG. 2. While one alternative is toshut down all functions when the telephone is turned off, it ispreferable that the detector remains on whether or not the telephone hasbeen turned off or not. Upon detecting the agent, the detector sends asignal to the supervisory/control unit of the telephone, as shown instep 21. If the telephone had been turned off, the supervisory/controlunit “awakens.” Under step 22, an onboard processor is then engaged todetermine a confidence level C, i.e., how closely does the detectorresponse matches known agent signature patterns that a hazardous agenthas been detected. The confidence level C is checked against a thresholdvalue in decision step 23. If C does not exceed the threshold value, thetelephone 10 is re-initialized by step 24 and is returned to the“waiting” state after the initialization step 20.

If the confidence level C exceeds the threshold value, thesupervisory/control unit under its enhanced firmware causes one or morealarm packets to be sent across the wireless network 11 to indicate thedetection of a hazardous agent under step 25. The alarm packets includedata on the agent type, the intensity I of the detector's response tothe agent; the confidence level C, the model number of the detector; itsparticular serial number; and the detector's age. After waiting a fixedperiod under step 26, the telephone 10 loops back to the state precedingstep 22 for another determination of the confidence level C. The alarmpackets sent by step 25 trigger operations at the receiving cellulartelephone base station 12 to send the base station's identificationnumber, along with the alarm packets to the computer 15 through thecellular network 11.

The flow chart of FIG. 3 illustrates how the computer 15 initiallyhandles the alarm packets broadcast from the telephone 10 and basestation 12. FIGS. 4A and 4B chart the flow of operation of the computer15 to determine the existence of an alarm condition, among other things.

The flow chart in FIG. 3 begins with initialization step 30. Infollowing step 31, the computer 15 reads the received alarm packets fromthe telephone 10 and base station 12 to determine the particular agentdetected and the vicinity of the telephone from the identification ofthe telephone cell network base station 12 in communication with thetelephone in alarm. Vicinity refers to the area enclosing the cell ofthe base station 12 and the cells immediately surrounding that cell. Asused in the present invention, vicinities, each centered about a basestation 10, overlap with adjacent vicinities to avoid voids in mappingand to facilitate the tracking of hazardous agents.

The computer determines whether a telephone has already detected thatparticular agent in the vicinity of the telephone cell base station 12,by step 32. If so, step 36 is engaged by which the alarm packets areplaced into an Input Alarm Packet Queue for the particular agent andvicinity for processing by an active Alarm Mode routine, describedbelow. The process then returns to the initialization step 30 to startthe process over again.

If not, i.e., the agent alarm in that vicinity is new, the process movesto step 33 in which the E911 tracking routine is engaged to determinethe locations, r, and the uncertainty in locations, Δr, of alltelephones which are capable of detecting that agent type in thatvicinity. A density map D(i,j) of those telephones in the vicinity iscreated and maintained in next step 34. The indices i,j refer to adiscretized area block, each of which forms a constituent of thevicinity; m is an index to all the telephones being tracked, i.e., thetelephones in the area block i,j with sensors capable of detecting theparticular agent. Each area block i,j has an area Δz², the smallest areaof resolution, and the sum of the areas of all the area blocks in avicinity should equal the area of the vicinity.

The density value D(i,j) is calculated by iteration for the area blocki,j over m. For all telephones m of the area block i,j, if the block i,jfalls in a circle of uncertainty radius |Δr(m)| centered at r(m), thenD(i,j)=D(i,j)+(Δz ²)/(π|Δr(m)|²).

The greater the uncertainty in the location of telephone m, the smallerits presence in the area block i,j is presumed to be. If the location rof telephone m is in area block i,j and it is certain that thattelephone is in that area block, i.e., the uncertainty in location Δr issuch that area of uncertainty π Δr² is a minimum, or equal to Δz², thedensity D(i,j) is incremented by one. Integrating D(i,j) over a vicinityyields the number of telephones in the vicinity.

Then by step 35 the Alarm Mode routine described below is launched forthe alarming agent and vicinity and the process returns to theinitialization step 30 to start over again.

The Alarm Mode routine of FIGS. 4A and 4B locates the center location ofa detected agent and its likely point of origin. After initializationstep 40, the computer 15 by decision step 41 checks the status of theInput Alarm Packet Queue which is loaded by the FIG. 3 process. EachInput Alarm Packet Queue is particular to an agent and vicinity, thecell area enclosing the base station 10 and cell areas immediatelysurrounding that base station, as described previously. If there is noalarm packet in the queue, the process moves to step 55 which determineswhether a sufficient amount of time has elapsed since the initialreception of previous alarm packets, i.e., packets for that agent andvicinity. If a sufficient amount of time has passed, the alarm status isended, a potential false alarm is logged, a cleanup is performed by step56 and this process is terminated by step 57. It is assumed that thecomputer 15 runs a multitasking operating system in which processes areinitiated and terminated as needed. This allows the possibility ofsimultaneous incidents in multiple vicinities to be handled by thecomputer 15 running several processes of the Alarm Mode routineconcurrently.

Returning to the decision step 55 in the process at hand, step 41 isreached if a sufficient amount of time has not passed. If by thedecision step 41, there is an alarm packet determined to be in thequeue, the alarm packets are read by next step 42 to determine the agentintensity I, confidence level C, sensor model identification, thesensor's serial number and its age. In step 43, the position r of thetelephone which sent the alarm packet and the telephone's positionuncertainty Δr is determined from the E911 tracking list. Then by step44 a decision is made whether the current packets are from a telephonewhich is already on an Active Telephone List. If not, then a threatcredibility weighting factor W is determined by step 46 from the alarmpacket data on the sensor model, its serial number, age, and currentdata on the reliability of that sensor, its relative performance, andthe effects of aging upon that sensor model. Note that more current datacan be uploaded into the computers 15 as more information on thetelephone sensors becomes available. Step 47 then pushes the alarmpacket data, threat credibility weighting factor W and the telephonelocation r onto the Active Telephone List and a contamination map iscreated by step 48.

For each area block i,j and particular alarming agent, a contaminationvalue X(i,j) is created from the agent intensity I, confidence level C,threat credibility weighting factor W and the uncertainty Δr in thelocation of each telephone. X(i,j) is calculated iteratively for all thetelephones in the Active Telephone List indexed by k, with the equation:X(i,j)=X(i,j)+I(k)*C(k)*W(k)*F(k)

where F(k) is a factor ˜1/π|Δr(k)|². Note that the contamination valueincreases with increasing agent intensity, confidence and credibility,and decreases with the uncertainty in telephone location, as might beexpected.

Returning to the decision step 44, if the alarm packet underconsideration is from a telephone which is already on the ActiveTelephone List, then the process branches to step 45 by which the ActiveTelephone List is updated with current alarm packet information. Theprevious location r, agent intensity I, confidence level C data from thetelephone are overwritten by the present data of the telephone underconsideration. Then the process moves to step 48 where the contaminationmap with contamination values X(i,j) are calculated, as explainedpreviously.

Step 49 follows step 48. For all area blocks i,j, the contaminationvalues X(i,j) are reduced in proportion to the density of similarsensors D(i,j) in each area block i,j so as to remove any skew due tovariations in the density of cellular telephones. For example, threetelephones in alarm in an area with only three telephones should weighmore heavily than an area with 20 telephones and only three in alarm.Then step 50 integrates the contamination values X(i,j) over allconstituent area blocks i,j in the vicinity, i.e., the area of the cellcovered by the cell base station and surrounding cell areas. It shouldbe noted again that the cell telephones 10 in alarm whose cell basestations 12 are surrounded by different cell base stations 12 aretracked by separate processes of the Alarm Mode routine and separatecontainment maps are created.

Returning to the present process, the result is compared with apredetermined threshold value T by decision step 51. If the thresholdvalue T is exceeded, a weighted averaging of X(i,j) is calculated instep 52 to find the likely center location of the detected hazardousagent. That is,

${r({center})} = {\sum\limits_{i,j}\frac{{X\left( {i,j} \right)}*{r\left( {i,j} \right)}}{X\left( {i,j} \right)}}$

In step 53 the center location of hazardous agent is extrapolated to theprobable origin, such as a point of deliberate release, of the hazardousagent from the best available wind velocity data and the elapsed timesince the reception of the first alarm packet. Then an alert is issuedin step 54 to any organization or team assigned to respond to thedetected hazardous agent. Software which tracks the hazardous agent isalso launched. Then the process is terminated by step 57. Again, itshould be noted that the cell phones 10 continue to broadcast alarmpackets and the alarm processing routine described with respect to FIG.3 continues to the packets onto the Alarm Packet Queues. These laterpackets are handled by a separate agent tracking routine (not presentlydetailed) launched in step 54.

Returning to the decision step 51, if the threshold value T is notexceeded, the process returns to step 41.

Thus the present invention offers an inexpensive, easily installed,low-maintenance network system for is On the other hand, the presentinvention provides for a network system which is inexpensive to operatewith easy installation and low maintenance costs for the detection andlocation of hazardous agents which have been loosened onto the public,intentionally or not.

Therefore, while the description above provides a full and completedisclosure of the preferred embodiments of the present invention,various modifications, alternate constructions, and equivalents will beobvious to those with skill in the art. Thus, the scope of the presentinvention is limited solely by the metes and bounds of the appendedclaims.

1. A cellular telephone network-based system for detecting hazardousagents, said cellular telephone network capable of locating cellulartelephones in said network, said system comprising a plurality ofcellular telephones in public circulation, each cellular telephonehaving at least one detector for detecting at least one hazardous agent,said cellular telephone broadcasting over said cellular telephonenetwork at least one alarm packet upon detecting said hazardous agent;and at least one computer interconnected with said plurality oftelephones by said cellular telephone network for processing said alarmpacket and setting an alarm condition for said hazardous agent in avicinity of said cellular telephone configured to calculate based uponalarm packets from other telephones with detectors for said hazardousagent in said vicinity, said calculations including determination of alevel of contamination of said hazardous agent in said vicinity andintegration of said level of contamination of said hazardous agent oversaid vicinity, with bias due to variations in cellular telephone densityover said vicinity removed, to determine whether a result of integrationexceeds an alarm threshold.
 2. The system of claim 1 wherein saidcalculations include determination of a level of contamination of saidhazardous agent in said vicinity and integration over said level ofcontamination of said hazardous agent over said vicinity to determinewhether a result of integration exceeds an alarm threshold.
 3. Thesystem of claim 1 wherein said calculations include adjusting for theage of said at least one detector of said cellular telephone in alarm.4. The system of claim 1 wherein said calculations include adjusting forthe reliability of said at least one detector of said cellular telephonein alarm.
 5. The system of claim 1 wherein said computer further createsa map of area contaminated by said hazardous agent.
 6. The system ofclaim 5 wherein said computer further determines a likely origin of saidhazardous agent.
 7. The system of claim 6 wherein said computerdetermines said likely origin of said hazardous agent from wind velocitydata.
 8. The system of claim 7 wherein said computer further predictsspread of said hazardous agent from said wind velocity data.
 9. Thesystem of claim 1 wherein said hazardous agent comprises biological,chemical or radioactive material.
 10. The system of claim 1 wherein saidcalculations include compensating for any uncertainty in telephonelocations.
 11. In a system based on a cellular telephone network havinga plurality of cellular telephones in public circulation, each cellulartelephone capable of detecting one or more hazardous agents and beinglocated by said cellular telephone network, a method comprisingreceiving an alarm packet from any of said cellular telephones in publiccirculation responsive to detection of a hazardous agent, parsing saidalarm packets to remove identifying data of said hazardous agent and acellular telephone base station in communication with said telephone;determining a level of contamination of said hazardous agent in saidvicinity from alarm packets from other telephones in said vicinity basedon said identifying data; mathematically integrating said level ofcontamination over said vicinity, including eliminating bias due tovariations in cellular telephone density over said vicinity; anddetermining whether a resulting integration value exceeds a threshold todetermine whether an alarm condition for said hazardous agent in saidvicinity exists.
 12. The method of claim 11 wherein said contaminationlevel determining step includes accounting for the age of a detector ina cellular telephone in alarm.
 13. The method of claim 11 wherein saidcontamination level determining step includes accounting for thereliability of a detector in a cellular telephone in alarm fromreliability data.
 14. The method of claim 11 further comprising creatinga map of area contaminated by said hazardous agent.
 15. The method ofclaim 11 further comprising determining a likely origin of saidhazardous agent.
 16. The method of claim 15 wherein said likely origindetermining step includes using wind velocity data.
 17. The method ofclaim 16 further comprising predicting spread of said hazardous agentfrom said wind velocity data.
 18. The method of claim 11 wherein saidhazardous agent comprises biological, chemical or radioactive material.19. The method of claim 11 wherein said contamination level determiningstep includes compensating for any uncertainty in telephone locations.